.i5-content {
    width: 100%;
    max-width: 1349px;
    height: 803px;
    .i5-change{
        width: 100%;
        max-width: 1349px;
        height: 100%;
    .i5-img-list {
        float: left;
        &>li {
            width: 25%;
            height: 270px;
            background: white;
            display: inline-block;
            margin: 0;
            margin-left: -5px;
            margin-top: -5px;
            .intro1{
                width: 100%;
                height: 100%;
                background: rgba(255,0,0,0.7);
                font-size: 28px;
                color: white;
                line-height: 270px;
                text-align: center;
                
            }
            img {
                width: 100%;
                height: 100%;
                float: left;
                
            }
            .first {
                width: 100%;
                height: 100%;
            }
        }
    }
}
}
//响应式
    @media only screen and (min-width: 768px) and (max-width: 1024px){
        .i5-content {
                   width: 100%;
           height: 100%;
        .i5-change{
        width: 100%;
    
    height: 100%;
    
    .i5-img-list {
        float: left;
        &>li {
            width: 50%;
            height: 270px;
            background: white;
            display: inline;
            margin: 0;
            img {
                width: 50%;
                height:  270px;
                float: left;
            }
            .first {
                width: 50%;
                height: 270px;
            }
        }
    }
  }
    } 
    }

    @media only screen and (max-width: 768px){
                 .i5-content {
                   width: 100%;
           height: 100%;
        .i5-change{
        width: 100%;
    
    height: 100%;
    
    .i5-img-list {
        float: left;
        &>li {
            width: 100%;
            height: 270px;
            background: white;
            display: inline;
            margin: 0;
            img {
                width: 100%;
                height:  270px;
                float: left;
            }
            .first {
                width: 100%;
                height: 270px;
            }
        }
    }
  }
    } 
            }